On 08/16/07 00:56, pankaj jain wrote: > I have a machine with 3 interfaces > eth0: 10.19.0.102 mask (255.255.255.0) > eth1: 10.19.1.102 mask (255.255.255.0) > eth2: 10.29.51.102 mask (255.255.255.0) Ok, > all three are connected in a same switch (no vlans configured). I > want arp requests to be responded by the associated interface only, > and not by other interfaces. Ok, > I have added following rules. > arptables -A INPUT -i eth0 --opcode Request -d 10.19.0.102 -j ACCEPT > arptables -A INPUT -i eth1 --opcode Request -d 10.19.1.102 -j ACCEPT > arptables -A INPUT -i eth2 --opcode Request -d 10.19.51.102 -j ACCEPT > arptables -A INPUT -i !eth0 --opcode Request -d 10.19.0.102 -j DROP > arptables -A INPUT -i !eth1 --opcode Request -d 10.19.1.102 -j DROP > arptables -A INPUT -i !eth2 --opcode Request -d 10.19.51.102 -j DROP > > DROP rules with [!] are not working. Hum. I would not think that you even needed the ARPTables rules to prevent the wrong interface from responding to an ARP request for another IP. Are you seeing this happen? Or is the purely preventative? > but if I remove the interface part it works fine > arptables -A INPUT -i eth0 --opcode Request -d 10.19.0.102 -j ACCEPT > arptables -A INPUT -i eth1 --opcode Request -d 10.19.1.102 -j ACCEPT > arptables -A INPUT -i eth2 --opcode Request -d 10.19.51.102 -j ACCEPT > arptables -A INPUT --opcode Request -d 10.19.0.102 -j DROP > arptables -A INPUT --opcode Request -d 10.19.1.102 -j DROP > arptables -A INPUT --opcode Request -d 10.19.51.102 -j DROP In short, you are allowing the ARP request for the specific interface / IP pair and then dropping any other ARP requests. You really could re-write the above as such: arptables -A INPUT -i eth0 --opcode Request -d 10.19.0.102 -j ACCEPT arptables -A INPUT -i eth1 --opcode Request -d 10.19.1.102 -j ACCEPT arptables -A INPUT -i eth2 --opcode Request -d 10.19.51.102 -j ACCEPT arptables -A INPUT --opcode Request -j DROP Rather I think this will work, but I can not guarantee that you will not have to take some precautions to make sure that you don't effect other possible interfaces (loop back / dummy / etc). Grant. . . .
